In so called allergic diseases which develop atopic dermatitis, bronchial asthma, food allergy, and the like, an allergen enters the body and combines with IgE on mast cells or basophils. Then, local inflammation is induced by histamine secreted from these cells. In order to produce IgE, functional differentiation of T cells that produce Th2 cytokines such as IL-4 or IL-13 that are important for class switching of immunoglobulin is important, and thus allergic constitution is considered to be in a state of Th2 dominance. Th2 cytokines such as IL-3, IL-4, IL-6, or IL-13 play a critical role in the proliferation or differentiation of effector cells such as mast cells or basophils.
Thus, the cytokines are involved in various reactions. Therefore, when sensitivities of these cells to these cytokines vary, big differences in the resultant reactivity may be caused. It is considered that the sensitivity of effector cells to cytokines is increased in an area where the allergic-inflammation occurred.
On the other hand, there have been many attempts to elucidate allergy-related phenomena at the molecular level using a specific cell line. As such a cell line, a novel mast cell line which maintains the functions of mast cells and does not involve c-Kit autophosphorylation is known (Japanese Patent Application Laid-Open (JP-A) No. 2004-215581). Therefore, it is suggested that the cell line, an NCL-2 cell line, is likely to exhibit a similar response to drug stimulation to that of a normal mast cell line because the cell line is not a tumor mast cell line. Consequently, it is described that the proliferation, differentiation, and functions of mast cells can be analyzed in detail by using this cell line.